Valves are broadly elliptic with rounded, sometimes slightly protracted apices. The raphe valve is concave and the rapheless valve is convex. The raphe valve has a narrow, straight axial area, widening towards a rhomboid central area. The raphe is straight with simple ends. Terminal raphe fissures are absent. The axial area of the rapheless valve is broad, rhomboid, with a horseshoe depression on one side that extends to the valve margin. Striae are biseriate and radiate.
Platessa strelnikovae has been so far found in sediments of three lakes in Vermont and Maine. These lakes are soft-water, circumneutral and mesotrophic.
Potapova, M. (2014). Platessa strelnikovae. In Diatoms of North America. Retrieved November 23, 2024, from https://diatoms.org/species/platessa_strelnikovae
The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Platessa strelnikovae from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:
ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.